


An Experiment

by abbyinbookland



Category: Harry Potter - J. K. Rowling
Genre: F/M, Female Reader, Harry Potter - Freeform, Harry Potter smut, James Potter Lives, James Potter x reader - Freeform, Marauders, Marauders Era (Harry Potter), Multi, NSFW, POV reader, Reader-Insert, Sirius Black Smut - Freeform, Sirius Black x reader - Freeform, Young James Potter, Young Sirius Black, harry potter fanfiction, harry potter oneshot, marauders smut, x Reader
Language: English
Status: In-Progress
Published: 2021-03-07
Updated: 2021-03-07
Packaged: 2021-03-13 20:09:28
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,345
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29906436
Author URL: https://archiveofourown.org/users/abbyinbookland/pseuds/abbyinbookland
Summary: James and Sirius try out a sex toy on F/n.Warnings: Smut (teasing, fingering, female oral, sex toy, degradation, cursing, slight overstimulation, slight begging)Abbreviation(s) used: f/n - first name, l/n - last name
Relationships: James Potter & Reader, Sirius Black & Reader
Kudos: 12





	An Experiment

**Author's Note:**

> This was inspired by one of my favorite parts of Fifty Shades Darker, if you've seen it you know what I'm referring to. If not, feel free to do some research ;)

**Hogwarts**

**September 2**

“Hey, L/n.” James greeted, plopping down next to me on the couch. Sirius followed, sitting on my other side. 

“Hey guys!” I beamed at them, “How was your summer?”

They shared a look I couldn’t translate and I watched them curiously. What were they planning? “Glad you asked,” James grinned, “that’s exactly what we came to talk to you about.”

“Why do I feel like this is going to be more than just catching up?” I groaned, sinking into the couch. They liked to drag me into their schemes, and that usually meant me being their test subject.

“Well, during the summer James and I went to some Muggle shops..” Sirius began.

“..And we found these.” James finished, reaching into his pocket and pulling out a string of two small metal balls. 

“What are those?” I asked, confused.

“They’re called Kegel balls.” 

“And?”

“And they’re a sex toy.” Sirius whispered into my ear, causing a shiver down my spine.

I jumped up, looking between them with wide eyes. “What? No!” I scolded. “I’m not trying out a sex toy for you.” I whispered loudly, suddenly aware there were other people in the common room.

James fake-pouted up at me, “But F/n, I bought them just for you.”

I shook my head, despite the small thrill I felt at the thought of James _wanting_ to use a sex toy on me. “Absolutely not.”

“Aw, pup..” Sirius stood up next to me and cupped my face, caressing my skin with his thumb. “You wouldn’t want to disappoint us now would you?” he brought his face closer to mine, his eyes clouded with mischief, “Besides, there’d be nothing but pleasure in it for you.”

I looked down at his lips, gulping down my sudden desire. The amount of times I had imagined both of them against me— _inside_ me—should be considered a sin. 

I cleared my throat, bringing myself from my clouded state of mind. I wouldn’t show them how into this I actually was. “Fine.” I said, stepping out of Sirius’ grasp to look at James.

He basically jumped up from the couch, “See Padfoot, I told you she’d do it.”

I scoffed and shook my head at him, “Let’s just get this over with.”

The two grinned at me, leading me up to their dorm. I sat down on the edge of Sirius’ bed while they stood eagerly in front of me.

I held out my hand to James, “Well, give them here.”

“Oh, no F/n. You’ll need help.” He chuckled. 

I felt my face warm a bit, I hadn’t thought about how they were actually _used_. “Right.”

“Well first..” Sirius knelt down in front of me, running his hands up the sides of my thighs.

My heart skipped a beat and I squirmed, feeling arousal spread over my cunt. “Sirius-”

He smirked up at me devilishly, “Don’t get too excited, pup. We just need to remove these.” He hooked his index fingers under the waist of my panties, pulling them down my legs. 

The cold air hit my arousal, and I swallowed a gasp. I felt heat rise to my face as I realized how exposed to them I was.

“Come here, love.” James encouraged, guiding me off the bed with his hands on my hips. “Now comes the fun part.”

I looked up at him nervously, my hand resting on his chest. He brought his mouth to my ear, his breath tickling my neck. “Turn around.” he whispered. 

I repressed a groan and did as I was told. Something told me they were trying their best to turn me on. James and Sirius had always teased me, but never in a sexual way before—which is why I had been so surprised that they bought a _sex toy_ to test on me. 

“Good girl.” James praised, pushing my back with his hand to show I needed to lean over.

Forearms resting on the mattress, I inhaled sharply as James ran a finger over my folds. “I knew you were enjoying this, F/n.” he fake-gasped. “You’re soaking wet.” he teased, playing with my arousal.

“James-” I moaned, instantly realizing my mistake.

Sirius chucked, “Wow James, we finally heard that pretty mouth of hers.”

“Won’t be the last time.” James growled, inserting a finger into my cunt. 

“Mm.” I moaned again, my back arching, and pushed back onto his finger.

He chuckled darkly, “Who knew you were such a slut?” He pulled out, much to my disappointment. 

“Now, it’s a good thing you're such a horny slut, F/n.” he stated, kneading my ass.

He paused and I realized he was waiting for a reply, “Why’s that, James?” I breathed, finally aware of the situation I was in.

“Because now we don’t need to lube them. We can just..” he pushed the first ball into my cunt with no warning, causing me to gasp. “..get to the best part.” he finished, pushing the second ball in.

A moan tore from my throat. The balls might’ve been small but they were still heavy enough to be pleasurable. 

“Come on, pup.” Sirius wrapped his arm around my waist and helped me stand up so I was leaning back on his chest. I swallowed another moan as the balls adjusted to my movements. 

I looked over at James in time to watch him lick my arousal off his finger, lust in his eyes as they met mine. “How do they feel, love?” he smirked at my flustered appearance. 

I cleared my throat to try and restore my composure, “Fine.” 

The two boys laughed. “Going to ignore that you just had your pussy on display for us? Pathetically moaning for James to touch you?” Sirius breathed into my ear, rubbing my lower stomach. 

I squirmed as he put some pressure there, causing the balls to press against my g-spot. “Sirius..”

He tugged on my ear with his teeth in response, and I felt his erection against my back. It seemed I wasn’t the only one turned on right now. 

“Okay, let’s try some things.” James announced, and Sirius let go of me.

I suddenly remembered that I was still missing a piece of clothing. “Wait, my underwear-” I turned to Sirius expectantly.

He just shook his head at me teasingly, and pulled the cloth from his pocket. “I’ll be keeping these.” 

“But-”

“This is an experiment, love.” James said, snaking his arms around my waist, “And the last time I checked we were the ones in charge.” 

He pulled me closer to him, and I felt his bulge as well. Fuck. My pussy pulsed at the thought of both of them. I ground up against him, earning a groan in return. He stopped my movements with his hands on my hips. “Stop it. This is about you, not us.” he growled.

“Sorry.” I knew how James could get if I disobeyed during one of his plans, and I had learned a long time ago to do as I was told.

“Now then.. Let’s see how these balls work, hm?” he said, and began to tickle me.

“James.” I laughed, “James, please, you know I hate being tickled I- Ohh..” I moaned as my laughs vibrated the balls inside me.

“Oh, this is going to be fun.” James chuckled against me.

Sirius grinned at us, “Come on, let’s go to breakfast.”

Both boys turned to go, leaving me standing pathetically turned on in the middle of the room.

“Wait, are we done?” my voice sounded almost pitiful—begging for their attention. For them to touch me.

James snickered at me, his hand resting on the doorknob, “If you’re asking if the experiment’s done you’re sorely mistaken, love.”

At my confused expression Sirius explained, “We’re going to see what happens throughout the day.”

“You mean I have to wear these all day?”

Their eyes were dark as they nodded.

“I- guys, I can’t do that.. I’ll be horny and wet all day and-”

“And what if you accidentally moan around people? That’s the plan, love.” James’ eyes were clouded, as if the thought of me wet all day because of _him_ was the best idea ever. 

I gaped at them, unsure what to say.

“Come on, it’ll be fun.” Sirius encouraged.

“You guys aren’t going to purposefully try to make me moan are you?”

The expression they gave was response enough. I was in for a long day.

* * * * *

Throughout the day James and Sirius tried their best to draw reactions from me, which made the balls jiggle around—creating _lots_ of pleasure. And while making me laugh uncontrollably was nothing new, they’d also brush their fingers along my spine while walking past in the hall or up my thighs while in class, causing me to shiver. 

All this stimulation built up a knot in my core, bringing me closer and closer to release. And also increased my arousal.

Once, while in Potions, I coughed and almost came—James just sent me a cocky and knowing look as I tried my best to hold in a moan. I glared back.

It also didn’t help that no one else knew, making my interactions throughout the day almost impossible. I thought I’d die of embarrassment when Remus made me burst out laughing in the library, drawing a moan from my lips which I quickly explained as pain from a stomach ache. Thankfully, innocent Remus believed me and suggested I go see Madam Pomfrey.

At the end of the day I weakly made my way up to James and Sirius’ dorm, my shaking legs making it difficult to even walk up the stairs.

I walked in to see them longing on their beds, going about their business as if nothing was going on. “You assholes.”

“Well hello to you too, love.” James greeted me, smirking at my shaking legs, “How was your day.”

“Literal Hell.” I growled, plopping down on Remus’ empty bed, fearful that my legs might not be able to hold me up much longer. 

“I’m sorry to hear that.” Sirius drawled, pretending to be only half listening.

I finally broke. “Can you guys just touch me already? I’m soaking wet.” I whined, rubbing my thighs together. 

“I thought you’d never ask.” James breathed darkly, making his way over and rubbing his hands up and down my thighs, “You’ve been such a good girl. Hasn’t she Sirius?”

“Oh, yes.” he agreed, sitting behind me and rubbing my back, “She obeyed the rules all day.”

James cooed at me, “Well then, let’s get these balls out first.” 

He guided me to lay back, my head resting on Sirius’ lap. Spreading my legs, he trailed his fingers down my thighs, causing me to shiver.

“James-” I wasn’t embarrassed at the thought of being exposed to them anymore, overwhelmed by my desire. I had wanted them to touch me all day, even daydreaming of them fucking me senseless over my desk.

“Patience, pup.” Sirius ordered, stroking my hair.

James finally reached my aching cunt, ghosting over my heat before slowly pulling on the string. The balls fell out with a soft, wet sound, dripping with my arousal.

Both of the boys let out throaty noise, instantly turned on by the sight. James brought the balls up to my mouth, “Open.”

I obeyed, closing my lips around the string as I sucked my own taste from the toy.

Sirius groaned down at me, his erection poking my head.

James pulled the toy away, the balls leaving my lips with a pop. He set them aside, kneeling down to inspect my exposed—and aching—cunt. “You’re _soaking_ , love.” 

He used two fingers to scoop some arousal from my folds, bringing them to his tongue with a hum. I squirmed at the scene.

“Impatient are you?” Sirius asked, massaging my right boob.

“Please.” I groaned.

James laughed, pushing my skirt up around my hips, “Don’t worry, love. Good girls get rewarded.” His breath tickled my cunt, causing me to gasp.

He left open mouthed kisses along my thighs, and Sirius took the opportunity to remove my shirt and bra.

“Merlin..” He moaned at the sight of my tits, bringing his mouth down to suck on one while palming the other.

James hungrily tongued circles on my clit, causing my back to arch. He added two fingers inside me, my walls pulsing around him.

The two boys continued their tasks, James sucking on my throbbing nub and Sirius sucking and nibbling on my tits—covering them with bruises.

I already felt the pressure in my core build towards release, extremely sensitive from today’s overstimulation. 

James felt me tighten around his fingers, quickening his pace. My chest heaved with my breaths, my thighs shaking around James’ head. 

Sirius, noticing how close I was, pinched my other nipple between his fingers, shooting more pleasure to my core.

I moaned beneath Sirius, turned to a blubbering mess. I breathed curse words between my unholy moans, lost to oblivion by my inevitable release.

“James-” “Sirius-” I moaned their names as I felt the knot in my stomach start to unwind, both boys humming against me as permission.

“Fuck!” I practically screamed as I orgasmed, my hips bucking. 

James pulled his fingers from my cunt, hungrily replacing them with his mouth to taste my release. I tugged on his hair, pulling him closer as I came on his face. 

I lay there shaking as I slowly came down from my high, barely realizing James pull away licking his lips, his chin glazed with my juices. Sirius rubbed my shoulder lovingly as they waited for my euphoria to calm.

“Shit.” I breathed.

James chuckled at me, “Worth the wait?”

“Definitely.” I sat up and leaned back on Sirius, “I just- wow.”

“Maybe we should do that more often then, hm?” Sirius proposed, wrapping his arms around me.

“Yes please.” I moaned, closing my eyes.

“As long as no one tells Mooney what we just did on his bed.” James suggested, pointedly looking at the small puddle on the sheets.


End file.
